In multiphase switching power converters, there are multiple inductors and corresponding power switches. Ideally, the currents through the various inductors are all equal. But non-idealities lead to current imbalances for the inductors. Such a current imbalance can cause the inductors to enter into saturation. It is thus conventional to implement current balancing techniques in a multiphase switching power converter to balance the currents across the inductors.
Currently, some conventional methods to balance the inductor currents operate by changing the slope of a ramp voltage for a pulse width modulator (PWM) of the power converter. This change in slope of the ramp voltage will adjust the duty cycle of the PWM for a given power switch and in turn adjust the current through the corresponding inductor. However, since these methods change the slope of the ramp voltage, these methods have the disadvantage of impacting the closed-loop transfer function, which can affect the stability of the switching power converter.
Accordingly, there is a need in the art for an improved current-balancing scheme for multiphase switching power converters to ensure robustness of the power converter regulation.